Histology and cytochemistry of human skin. IX. The distribution of non-specific esterases.

1. In the epidermis non-specific esterase activity outlines a strongly reactive band between the stratum granulosum and the stratum corneum. In the epidermis of the palm, there is no such esterase-rich band. 2. The outer sheath of active hair follicles has strong enzyme activity. The degenerating hair bulb in catagen follicles is very strongly reactive, and clusters of cells around the hair club in quiescent follicles are rich in enzyme activity. 3. Strong enzyme activity is found in young sebaceous cells, while decaying sebaceous cells and newly formed sebum are unreactive. Old sebum, however, is very intensely reactive. 4. Only the "dark" cells of eccrine sweat glands show a reaction; the "clear" cells are negative. 5. The cells of axillary apocrine glands abound in enzyme.